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Lactase
Enzyme that breaks down the milk sugar lactose into glucose and galactose. Persons with a deficiency of lactase in the gut can develop abdominal cramping and diarrhea after ingesting milk products.

Lactase deficiency
Not enough of an enzyme called lactase in the small intestine to digest lactose, a prominent component of milk and most other dairy products. Lactose is sometimes also used as an ingredient in other foods, so anyone with lactase deficiency should check food labels with care.

Lactic acidosis
Acidosis (too much acid in the body) due to the buildup of lactic acid in the body. Lactic acidois occurs when cells make lactic acid (from glucose) faster than it can be metabolized. The key signs of lactic acidosis include unusually deep and rapid breathing, vomiting, and abdominal pain. Lactic acidosis is a feature of different disorders. It is an important sign of diabetes that is out of control.

Lactobacillus acidophilus
The bacteria found in milk and fermented milk products, particularly yogurt with "live cultures" of L. acidophilus. L. acidophilus assists with the digestive process within the intestinal tract. It can be decimated by the use of antibiotics, and many health professionals urge people to use probiotics to counter this unfortunate side effect of antibiotic use.

Lactose
The sugar found in milk. The body uses the enzyme lactase to break down lactose into galactose and glucose.

Large intestine
Comes after the small intestine. Large because it is wider than the small intestine.

Liver
An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body.The liver has a multitude of important and complex functions. Some of these functions are to: Manufacture (synthesize) proteins, including albumin (to help maintain the volume of blood) and blood clotting factors. Synthesize, store, and process (metabolize) fats, including fatty acids (used for energy) and cholesterol. Metabolize and store carbohydrates, which are used as the source for the sugar (glucose) in blood that red blood cells and the brain use. Form and secrete bile that contains bile acids to aid in the intestinal absorption (taking in) of fats and the fat-soluble vitamins A, D, E, and K.Eliminate, by metabolizing and/or secreting, the potentially harmful biochemical products produced by the body, such as bilirubin from the breakdown of old red blood cells and ammonia from the breakdown of proteins. Detoxify, by metabolizing and/or secreting, drugs, alcohol, and environmental toxins.

Lymphocytes
A small white blood cell (leukocyte) that plays a large role in defending the body against disease. Lymphocytes are responsible for immune responses.